Si/Ge nanodot superlattices for Si-based photovoltaics

Philip Barletta, Geza Dezsi, Minjoo Lee, Changhyun Yi, Rama Venkatasubramanian

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We have grown Si/Ge nanodot superlattices via low-pressure chemical vapor deposition in order to analyze their performance as thin-film solar cells. Self-assembled Ge nanodots are included in the base region in order to boost absorption of near-infrared photons and to increase short-circuit current density, Jsc. At a relatively low dot density of 5.5x109 cm-2, both 20- and 40-period cells exhibited a fill factor of 70% and opencircuit voltage (Voc) of 0.51V, closely matching previously reported devices grown by molecular beam epitaxy. The 20- and 40-period cells had similar spectral responsivity for λ=400-550 nm, but the thicker base of the 40-period cell enabled it to attain higher responsivity for wavelengths in the range of 550-900 nm. When we increased the dot density by 55% while holding the number of periods at 40, Voc dropped significantly due to a combination of lower bandgap and higher dislocation density. Work is in progress to integrate such SiGe-nano-materials based PV devices with ultra-thin Si PV, to obtain higher efficiencies as well as minimize the use of Si.

Original languageEnglish (US)
Title of host publicationIEEE SoutheastCon 2010
Subtitle of host publicationEnergizing Our Future
Number of pages4
StatePublished - May 31 2010
Externally publishedYes
EventIEEE SoutheastCon 2010 Conference: Energizing Our Future - Charlotte-Concord, NC, United States
Duration: Mar 18 2010Mar 21 2010

Publication series

NameConference Proceedings - IEEE SOUTHEASTCON
ISSN (Print)0734-7502


OtherIEEE SoutheastCon 2010 Conference: Energizing Our Future
CountryUnited States
CityCharlotte-Concord, NC

ASJC Scopus subject areas

  • Computer Networks and Communications
  • Software
  • Electrical and Electronic Engineering
  • Control and Systems Engineering
  • Signal Processing

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